Positive displacement piston pump



June 28, 1966 H. E. PINKERTON 3,257,953

POSITIVE DISPLACEMENT PISTON PUMP Filed Aug. 14, 1964 2 Sheets-Sheet 1 FIG. 32 FIG. 3

H. E. PINKERTON POSITIVE DISPLACEMENT PISTON PUMP 2 Sheets-Sheet 2 June 28, 1966 Filed Aug. 14, 1964 FIG. 5

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3,257,953 PGSITIVE DISPLACEMENT PISTON PUMP Harry E. Pinkerton, P.0. Box 387, Mill Neck, N.Y. Filed Aug. 14, 1964, Ser. No. 389,702 9 Claims. (Cl. 10338) The present invention relates to improvements in valveless positive displacement pumps; and this application isa continuation-in-part of my earlier filed application SN 253,475 of January 23, 1963, now Patent No. 3,168,872.

The present invention has, for one of its principal ob ects, a positive displacement pump advantageously incorporatmg a piston adapted to both reciprocateand oscillate relative to the cylinder and, at the same time, a

pump that is highly accurate and capable of functioning without the use of valves in many fluid handling applications as, for example, in the packaging portion of industry, filling ampules, vials, bottles and other such containers in a range of fluid viscosities from that of aqueous solutions to lard-like substances where reproducible accuracy from injected shot to shot permits realistic economies to such operations not to mention the uncomplicated low cost tool also peculiarly adapted for handling chemicals in accurate dosing of trace materials in continuous fluid systems, i.e., water treatment, industrial process, pipeline, etc.

Another object is to provide a positive displacement piston pump with a scavenger duct means for redirecting pump fluid that may have escaped between the associated surfaces of the piston and cylinder, with a squeegee means incorporated for effectively wiping the piston dry during the retraction stroke of the piston.

A further object is to provide a positive displacement pump in which the piston both reciprocates andoscil-,

lates relative to the cylinder upon the acceptance of rotational energy transmitted from a drive means the output of which is substantially normal to the axis of the piston; and, at the same time, include in such pump an adjustment means for flow rate from zero to a maxi- A pump incorporating the teachings of the present invention employs a ducted piston which reciprocates and oscillates synchronously in a bi-ported cylinder. The piston duct is so arranged as to connect the ports alternately with the pumping chamber. Under such circumstances, one port will communicate with the pumping chamber on the down stroke of the piston whereas the other port will be exposed to the chamber on the piston upstroke. As was the case with the pumping units of my earlier application, this invention contemplates at least three cylinder-piston arrangements for purposes of covering a majority of modern day fluid handling requirements. These arrangements are, respectively, termed monoplex, double monoplex and duplex. Each arrangement lends itself advantageously to a scavenger duct means whereby piston and gland bypass fluids can be returned at negative pressure to the suction side of the pump system.

In the several disclosed embodiments of this invention, a piston cylinder assembly is coupled with the output of a drive motor, with the axis of the motor output shaft being substantially normal to that of the piston and cylinder. For variable flow rates, it should be understood that a variable speed motor can be employed. The piston includes, at its outer end, a laterally projecting pin. A crank is interposed between the pin and motor output shaft to turn the pin upon rotation of the shaft and thereby induce longitudinal reciprocation of the piston as well as rotational oscillation thereof relative to the cylinder. In one of the contemplated embodiments disclosed herein, the length of crank arm is adjustable for purposes of varying flow rates.

past these ports.

Patented June 28, 1966 "ice with the cylinder sectioned to show both inlet and out-- let ports;

FIG. 3 is an enlarged fragmentary sectional view of the motor output shaft laterally extending piston pin with interposed crank for transferring rotational energy from the motor output shaft to the pin;

FIG. 4 is an enlarged cross sectional view taken along the-line 4-4'of FIG. 2;

FIG. 5 is an elevational view similar to FIG. 1 showing another embodiment of positive displacement piston pumping system wherein the crank is of fixed proportions thereby maintaining a constant flow rate; and

FIG. 6 is a plan view thereof.

Referring now to the embodiment of FIGS. 1 to 4, a positive displacement piston pump 30 is shown coupled with the output of a drive motor 32, both of which may be suitably mounted or suspended to suit the particular application. In this connection, the motor 32 may be secured by means of the anchoring bolts 34 and 36 suitably secured as by weld-ing to the motor housing. The pump 30 is suitably suspended or otherwise mounted on the housing of the motor 32 by means of a bracket extension 38 formed as an integral part of the pump cylinder. This bracket extension includes a transversely extending substantially flat plate 40 through which a suitable number of screws or threaded bolts 42 may extend to complete the coupling of the pump 30 to the motor 32.

Interposed between the motor 32 and pump 30 and suitably secured relative thereto is a reduction gear train 44 which operates to reduce motor output to the selected value. The pump cylinder 46 suitably accommodates the piston 48 adapted to be longitudinally reciprocal and rotatably oscillational relative thereto. The ex terior end of the piston 48 is conveniently adapted to be coupled with the gear down rotational output of the motor 32 by means of the crank 50 in a manner to be described in detail shortly.

In furtherance of the pumping action accomplished by the pump of this invention, the inner end of the piston 48 is provided with a cutout or recessed portion 52 functioning as a duct which, together with the cylinder vided with ports 56 and 58 adapted to perform respectfully as inlet and outlet ports and communicate with the pump chamber 54. Tubing may be suitably coupled with these ports as part of the circular system for fluid to be pumped. As will be readily appreciated, the forinterior at the head of the piston, cooperates in forming the cylinder pumpingchamber 54. The cylinder is proward end of the piston 48 is adapted to close off or seal each port depending upon the extent of relative rotation of oscillation of the piston in the cylinder. The duct 52 is adapted to simultaneously expose the pumping chamber 54 to the other port to permit free passage into the chamber of the pump fluid. The piston head operates to shear the fluid on the suction stroke as it rotates As will be appreciated by those skilled in the art, no suction check valve is needed since outlet pressure is never felt at the inlet port. Similarly, the outlet port is never opened to the inlet, therefore, a high discharge check is not necessary.

The outer end of the piston 48 has secured thereto a laterally projecting roll pin 57. The free end of this pin cooperates with the crank 50 in transforming rotational movement to both reciprocal and oscillating movement of the piston 48.

The crank 50 cooperates to transform this energy and in doing so is adjustably mounted on the motor output shaft 55 for purposes of adjusting the effective crank arm length. In this connection, the crank 50 includes an eccentric drive 59 rotatably mounted on the output shaft 55 and adapted to be secured in place by means of the set screw 60. In operation, the pin 57 bears against the eccentric drive 59. Therefore, rotation or turning of the drive 59 on the output shaft 55 will serve to increase or decrease the distance of the pin 57 to the axis of rotation of the shaft 55. In order to assure that the pin 57 maintains its desired contact with the periphery of the drive 59, a retaining hook 61 is adapted to be associated with the pin. This hook 61 is either adjustably mounted on a drive pin 62 in order to manually shift the hook into engagement with the pin 57 or, on the other hand, the drive pin 62 may be adjustable with respect to the drive shaft 55 in a radial direction and when the desired adjustment has been effected, it will be maintained in place by the suitably located screw. The stages of turning of the pin 50 with the shaft 55 is shown in dotted lines in FIG. 3. This movement of the pin 57 will induce longitudinal reciprocation to the piston 48. At the same time, the piston 48 will oscillate or rock to thereby expose the duct 52 to one port of the cylinder 46 to another. Thus, with the pin disposed relative to the output shaft 55 as depicted by solid lines in FIG. 3, the piston 48 will be at the end of its retraction stroke with pump fluid present in the pumping chamber 54. Assuming counterclockwise rotation as viewed in FIG. 3, the pin 57 will also rotate counterclockwise to expose the duct 52 to the outlet port 58 to thereby pump fluid from the chamber 54 out through the duct 52 and port 58. When the pin 57 reaches the position illustrated by dotted lines in FIG. 3, the end of the pumping or forward stroke of the piston 48 has been reached and the retraction stroke commences. With further rotation of the pin 57, the duct 52 will be in communication with the inlet port 56 to withdraw the liquid through the duct 52 into the pumping chamber 54. This cycle of operation is continued in fulfilling the desired performance of the pump of this invention (see numerals IIV of FIGS. 2 and 3).

As previously explained, the present invention contemplates the incorporation of a scavenger duct means which is generally designated by numeral 66. Thus, a slot 68 is provided in the walls of the cylinder 4-6 at the suction side of the pump and connects the inlet port 56 with the rear terminal end of the cylinder defined by a counter bore 70. A lip seal in the form of a relatively thin washer made of resilient material such as a filled Teflon is located at the rear end of the cylinder 46 and is provided with a central opening 74 which is smaller than the diameter of the piston such that u on thrusting the piston through the washer at assembly causes the hole to be enlarged through deformation in the direction of the counter bore. A seal nut 76 not only serves to maintain the washer associated with the rear end of the cylinder but also restricts reversal of the deformation. Thus, the sealing lip acts as a sequeegee to effectively wipe the piston dry on extraction from the cylinder when pasing through its retraction stroke.

In operation, any fluids, which migrate during the pressure stroke towards the atmosphere in the pistoncylinder clearance gap, arrive at the counter bore. There they are wiped from the piston by the lip seal and are returned through the scavenger duct 68 to the suction side of the system.

As will be appreciated by those skilled in the art, one of the greatest values of the scavenging duct means of this invention resides in the economies it affords in allowing use of simple lip-seal glands instead of complex and troublesome packing arrangements in the elimination of by-pass fluid losses. In addition, the lip-seal gland actually operates at negative pressure to provide completely dry piston shaft operation. Referring now to the embodiment of FIGS. 5 and 6, it should be understood that, in lieu of the adjustable crank 50, a fixed crank is provided. This crank is secured to the motor output shaft 55 by means of the set screw 152. The laterally extending pin 57 at the end of the piston 48 is formed at its end with a ball 154 which is disposed in an accommodating recess 156 in the crank 150. In order to provide lubrication during pump operation, a felt oiler 158 may be interposed between the ball 154 and inner surfaces of the crank 150. In this particular embodiment in lieu of the duct scavenging means 66, a mere O-ring 66 may be interposed between the piston 48 and cylinder 46 and be suitably disposed in an accommodating recess in the latter. In all other respects, the unit illustrated in FIGS. 5 and 6 is essentially the same as that of FIGS. 1 to 4. Accordingly, like parts will be similarly numbered with accompanying primes.

In addition, the operation of the pumping units is substantially the same.

Thus, the advantages of the present invention may now be appreciated. The component parts contributing to the pump units can be manufactured from metals, plastics or cermets as well as other materials. Basic simplicity of parts is also provided without limiting their versatility and application. These pumps can be employed for metering small or large flows in virtually any head to suction relationship. Without check valves danger of clog ing, cavitation and failure is avoided providing many years of troublefree service.

Other objects and advantages will become apparent to those skilled in the art after review of this disclosure taken in conjunction with the teachings contained in my earlier filed parent application. Although somewhat preferred embodiments of my invention have been disclosed herein, it should be understood that this invention is in no sense limited thereby and is to be determined by the scope of the appended claims.

I claim:

1. A pump comprising a cylinder having a cylinder wall defining an axial bore and piston movable therein, port means for introducing into and expelling a liquid from said pump and scavenging means incorporated in said pump for redirecting escaping liquid that escapes between the associated walls of the piston and cylinder, said scavenging means including a groove in said cylinder wall in fixed relationship to said port means and adapted to communicate with said port means during the movement of the piston and a squeegee means for wiping the piston of liquid in order that this liquid may be directed through the groove to the port means.

2. A pump comprising a cylinder having a cylinder wall defining an axial bore and piston movable therein, port means for introducing into and expelling a liquid from said pump, scavenging means incorporated in said pump for redirecting escaping liquid that escapes between the associated Walls of the piston and cylinder, said scavenging means including a groove in said cylinder wall in fixed relationship to said port means and adapted to communicate with said port means during movement of the piston, and a lip seal extending between the piston and cylinder for cooperating and controlling leakage of liquid there between.

3. A valveless positive displacement pump comprising: a cylinder having an inlet and outlet port; a piston in said cylinder for longitudinal reciprocation and rotational oscillation over an arc of less than 360 therein; said piston being formed with a duct means communicable with both of said ports during oscillation thereof, said piston adapted to provide with the cylinder interior a pump chamber adapted to vary in size upon reciprocation of the piston, said piston having an end disposed exteriorly of said cylinder; a pin extending laterally from the exterior end of the piston and means for rigidly connecting said pin to said piston; a drive means having an output shaft for inducing rotation of the shaft, the axis of the shaft being substantially parallel to the axis of the pin and at an angle to the axis of the piston; and coupling means for coupling the pin and the shaft to one another whereby upon rotation of the shaft said piston reciprocates and oscillates in a timed relationship relative to the cylinder to vary the pump chamber and, at the same time, expose said duct means to one of said ports and then the other to draw fluid to be pumped from one port through said duct means into the pump chamber and then out of the chamber through said duct means out through the other port, said coupling means including an adjustable motion transmitting device between said pin and said shaft for varying the extent of relative reciprocation of said piston in said cylinder.

4. The invention in accordance with claim 3 wherein scavenging means are incorporated in said pump for redirecting escaping fluid that escapes between the associated walls of the piston and cylinder.

5. A valveless positive displacement pump comprising: a cylinder having an inlet and outlet port; a piston in said cylinder for longitudinal reciprocation and rotational oscillation over an arc of less than 360 therein; said piston being formed with a duct means communicable with 'both of said ports during oscillation thereof, said piston adapted to provide with the cylinder interior a pump chamber adapted to vary in size upon reciprocation of the piston, said piston having an end disposed exteriorly of said cylinder; a pin extending laterally from the exterior end of the piston and means for rigidly connecting said pin to said piston; a drive means having i the shaft, the axis of the shaft being substantially parallel an output shaft for inducing rotation 'of the shaft, the 4 axis of the shaft being substantially parallel to the axis of the pin and at an angle to the axis of the piston; and coupling means for coupling the pin and the shaft to one another whereby upon rotation of the shaft said piston reciprocates and oscillates in a timed relationship relative to the cylinder to vary the pump chamber and,

at the same time, expose said duct means to one of said ports and then the other to draw fluid to be pumped from one port through said duct means into the pump chamber and then out of the chamber through said duct means out through the other port, said coupling means including a member connected to said shaft, said member having a recess, said coupling means also including a ball mounted on said pin, said ball being disposed in said recess and movable therein.

6. The invention in accordance with claim 5 wherein scavenging means are incorporated in said pump for redirecting escaping fluid that escapes between the associated walls of the piston and cylinder.

7. A valveless positive displacement pump comprising: a cylinder having an inlet and outlet port; a piston in said cylinder for longitudinal reciprocation and rotational oscillation therein; said piston 'being formed with a duct means communicable with both of said ports during oscillation thereof, said piston adapted to provide with the cylinder interior a pump chamber adapted to vary in isze upon reciprocation of the piston, said piston having an end disposed exteriorly of said cylinder; a pin extending laterally from the exterior end of the piston; a drive means having an output shaft for inducing rotation of the shaft,

Y 6 the axis of the shaft being substantially parallel to the axis of the pin and at an angle to the axis of the piston; and coupling means for coupling the pin and the shaft to one another whereby upon rotation of the shaft said piston recipnocates and oscillates in a timed relationship relative to the cylinder to vary the pump chamber and, at the same time,'expose said duct means to one of said ports and then the other .to draw fluid to be pumped from one port through said duct means into the pump chamber and then out of the chamber through said duct means out through the other port, scavenging means being incorporated in said pump for redirecting escaping fluid that escapes between the associated walls of the piston and cylinder, said scavenging means including a groove in said cylinder in fixed relationship with respect to one of said ports and adapted to communicate with one of the ports subject to suction during the cyclical movement of the piston, and a squeegee means for wiping the piston pump fluid in order that this fluid may be directed through the groove to the suction side of the pump.

8. A valveless positive displacement pump comprising:

a cylinder having an inlet and outlet port; a piston in said cylinder for longitudinal reciprocation and rotational oscillation therein; said piston being formed with a duct means communicable with both of said ports during oscillation thereof, said piston adapted to provide with the cylinder interior a pump chamber adapted to vary in size upon reciprocation of the piston, said piston having an end disposed exteriorly of said cylinder; a pin extending laterally from the exterior end of the piston; a drive means having an output shaft for inducing rotation of to the axis of the pin and at an angle to the axis of the piston; and coupling means for coupling the pin and the shaft to one another whereby upon rotation of the shaft said piston reciprocates and oscillates in a timed relationship relative to the cylinder to vary the pump chamber and, at the same time, expose said duct means to one of said ports and then the other to draw fluid to be pumped from one port through said duct means into the pump chamber and then out of the chamber through said duct means out through the other port, said coupling means being an adjustable drive connection extending between the shaft and said pin.

9. The invention in accordance with claim 8 wherein said adjustable drive connection is in the form of an ad justable cam adapted to be adjusted to vary the effective length of said adjustable drive connection and, consequently, the extent of reciprocation of said piston relative to the cylinder.

References Cited by the Examiner UNITED STATES PATENTS 313,353 3/1885 Mack 103 153 973,353 10/1910 Inokuty 103-157 1,099,155 6/1914 Ahlborn 103157 1,267,040 5/ 1918 Anderson 230--173 1,633,270 6/ 1927 Olsen 230-173 2,060,076 11/ 1936 High 103-157 2,070,203 2/1937 Gregg l03-l57 2,406,599 8/1946 Folke 103157 FOREIGN PATENTS 1,058,498 11/ 1953 France. 1,023,278 1/ 1958 Germany.

LAURENCE V. EFNER, Primary Examiner. 

1. A PUMP COMPRISING A CYLINDER HAVING A CYLINDER WALL DEFINING AN AXIAL BORE AND PISTON MOVABLE THEREIN, PORT MEANS FOR INTRODUCING INTO AND EXPELLING A LIQUID FROM SAID PUMP AND SCAVENGING MEANS INCORPORATED IN SAID PUMP FOR REDIRECTING ESCAPING LIQUID THAT ESCAPES BETWEEN THE ASSOCIATED WALLS OF THE PISTON AND CYLINDER, SAID SCAVENGING MEANS INCLUDING A GROOVE IN SAID CYLINDER WALL IN FIXED RELATIONSHIP TO SAID PORT MEANS AND ADAPTED TO COMMUNICATE WITH SAID PORT MEANS DURING THE MOVEMENT OF THE PISTON AND A SQUEEGEE MEANS FOR WIPING THE PISTON OF LIQUID IN ORDER THAT THIS LIQUID MAY BE DIRECTED THROUGH THE GROOVE TO THE PORT MEANS. 